Isoparaffin alkylation with a lighter olefin and subsequently with a heavier olefin

ABSTRACT

A PROCESS FOR ALKYLATING AN ISOPARAFFIN WITH A LIGHTER OLEFIN AND A HEAVIER OLEFIN BY CONTACTING THE ISOPARAFFIN WITH THE LIGHTER OLEFIN AND A FIRST ALKYLATION CATALYST IN A FIRST ALKYLATION ZONE, CONTACTING THE HYDROCARBON EFFLUENT FROM THE FIRST ALKYLATION ZONE WITH THE HEAVIER OLEFIN AND A SECOND ALKYLATION CATALYST IN A SECOND ALKYLATION ZONE, AND RECOVERING THE PRODUCT OF THE PROCESS FROM THE HYDROCARBON EFFLUENT FROM THE SECOND ALKYLATION ZONE.   D R A W I N G

`3,780,131 EFIN AND SUBSEQUENTLY J. E. SOBEL Dec. 18, 1973 ISOPARAFFINALKYLATION WITH A LIGHTER OL WITH A HEAVIER OLEFIN Filed July '7, 1972United States Patent O 3,780,131 ISOPARAFFIN ALKYLA'I'ION WITH A LIGHTEROLEFIN AND SUBSEQUENTLY WITH A HEAVIER OLEFIN Jay E. Sobel, Des Plaines,Ill., assignor to Universal Oil Products Company, Des Plaines, Ill.Filed July 7, 1972, Ser. No. 269,907 Int. Cl. C07c 3/52, 3/54 U.S. Cl.260--683A5 13 Claims ABSTRACT F THE DISCLOSURE BACKGROUND OF THEINVENTION This invention relates to a process for alkylating analkylatable isoparaliinic hydrocarbon with olelinic hydrocarbons. Morespecifically, this invention relates to a process for producing analkylation reaction product from an isoparaiiinic reactant, a lighterole-finie reactant and a heavier olefinic reactant, utilizingacid-acting alkylation catalysts. This invention further relates to theprocess for producing an alkylation reaction product having superiorqualities as a component of motor fuels, in comparison to the productproduced by previously employed alkylation processes.

Alkylation of isoparafinic hydrocarbons, such as isobutane, isopentaneand the like, with olelinic hydrocarbons such as propylene, butylenes,amylenes, and the like, is well known as a commercially important methodfor producing gasoline boiling range hydrocarbons. The C- Clohydrocarbons generally produced by the alkylation reaction are termedalkylate Alkylate is particularly useful as a motor fuel blending stockbecause of its high motor octane and research octane ratings, such thatit can be used to improve the overall octane ratings of gasolines tocomply with the requirements of modern automobile motors. Such highoctane products are particularly important in producing unleaded motorfuels of sufficient quality when it is desired not to employ alkyl leadcompounds in the fuel to meet octane requirements. A continuing goal ofthe art is to provide an isoparaffin-olefin alkylation process whichproduces an alkylate product having higher motor and research octaneratings than is possible using conventional processes.

Recent trends in motor fuel requirements and projections of futurerequirements in this area indicate that the production of motor fuelsdistilling at end points below about 300 F. may 'be desirable and/ornecessary to meet projected standards. Conventional isoparaliinolefinalkylation processes do not have the capacity to produce an alkylateproduct having a distillation end point low enough to be useful inproviding such low end point motor fuels. The process of the presentinvention provides a method whereby an alkylate product having asignificantly lower distillation end point than possible usingconventional processes may be produced, in addition to the increasedvalue of the product of the present process resulting from octane ratingimprovements.

In general, commercial` isoparaffin-olefin alkylation processes employisobutane as the isoparafiin and propylene and/or butylenes as theolefins. Catalysts utilized include hydrogen fluoride, sulfuric acid andother like Patented Dec. 18, 1973 ice acidic or acid-acting materials.The isoparafiin, olefins and catalyst are typically contacted in analkylation reactor, forming a reaction mixture. After the alkylationreaction is substantially complete, the reaction mixture is Withdrawnfrom the reactor and is separated into hydrocarbon and catalyst phasesin a separation zone, generally by settling in a settling vessel, andthe catalyst thus separated is recycled to the reactor for further use.The hydrocarbon phase produced is further processed, for example, byfractionation, to recover the alkylate product and to separateunconsumed reactants, e.g., isoparaiiin, for further use.

It has been found preferable to conduct isoparafiinolefin alkylationprocesses at particular conditions of temperature and pressure, and atspecific concentrations of reactants and catalysts in order to producean optimum yield of high quality alkylate product. A large molar excessof isoparaliin, relative to olefin, in the reaction mixture, generallyabout 10:1 to about 30:1, is one of the conditions required to provideeven an adequate product. It has been found desirable to employ as largean excess of isoparafiin as possible, since the quality of the alkylateproduct is improved thereby. Thus, a considerable amount of isoparaffinis generally recovered and recycled to the reactor after separation fromthe hydrocarbon phase of the reactor effluent. The large amount ofisoparaliin which must accordingly be passed, unreacted, through thealkylation reactor and settler and separated from the alkylate productnecessitates the use of fractionation equipment of large capacity inorder to provide an adequate separation of the product alkylate from theisoparafiin to be recycled. Limitations on the amount of excessisoparafiin employed are primarily of an economic nature. The expenseand difficulty of providing a large isoparafiin throughput and recyclemay be obviated, in part, through the use of the process of thisinvention.

It is known that higher quality alkylate may be produced, in thealkylation of different molecular weight olefins such as propylene andbutylenes, etc., with an isoparafiin, when one olefin, for example,propylene is separately alkylated with the isoparafiin at one set ofreaction conditions while, for example, butylenes are alkylated with theisoparaffin at a different set of reaction conditions. However, it hasbeen found necessary to maintain the same high molar excess ofisoparaffin to olefin in both the propylene alkylation reaction and thebutylenes alkylation reaction in order to provide an adequate product.The separate alkylation of, for example, C3 and C4 olefins has,therefore, been found uneconomical, because of the expense of providingseparate reactors for the C3 and C.; olefins when combined with theabove-noted expense and difficulties in handling the large molar excessof isoparaflin, to provide a high quality product.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a process for alkylating an isoparafiin with a lighter olefinand a heavier olefin. A further object of the present invention is toprovide a process for producing a superior alkylation reaction productfrom a lighter olefin, a heavier olefin and an isoparaiiin. Anotherobject of the present invention is to provide an isoparaiiin-olelinalkylation process having a reduced isoparan handling requirement, whilemaintaining a high isoparan concentration during the alkylationreaction.

In a broad embodiment, the present invention relates to a process forproducing an alkylation reaction product from an isoparaliinic reactant,a lighter olelinic reactant and a heavier olelinic reactant whichcomprises the steps of: (a) contacting said isoparafiinic reactant andsaid lighter olefinic reactant with a first alkylation catalyst in afirst alkylation zone at rst alkylation conditions; (b) recovering fromsaid lirst alkylation zone a rst hydrocarbons stream which comprises aportion of said isopara'nic reactant and a portion of said alkylationreaction product; (c) contacting said heavier oleinic reactant and atleast a portion of said rst hydrocarbons stream with a second alkylationcatalyst in a second alkylation zone at second alkylation conditions;(d) recovering from said second alkylation zone a second hydrocarbonsstream which comprises at least a portion of said alkylation reactionproduct; and (e) recovering said alkylation reaction product from saidhydrocarbons stream.

I have discovered a method whereby a lighter oleiinic reactant and aheavier olefinic reactant can be alkylated separately 'with an isoparainat different alkylation conditions preferred for separate alkylation ofthe two olens, providing a superior reaction product from both olefins.Simultaneously, the amount of excess isoparafn required for optimumalkylation conditions can be reduced. By passing the total charge ofisoparaim'c reactant into a tirst alkylation reactor with the lighterolenic reactant, charging the hydrocarbon eiluent from the rst reactorand the heavier olefnic reactant to a second alkylation reactor, andrecovering the alkylate product from the hydrocarbon eiuent from thesecond alkylation reactor, the separate alkylation of the lighter andheavier olens can be accomplished with an optimum concentration ofexcess isoparaflin for both the reactions in both reactors without thenecessity of providing separate isoparailin supplies to the two reactorsemployed.

DESCRIPTION OF 'I'HE DRAWING The attached drawing illustrates aparticular embodiment of the present invention. In the embodiment shown,isobutane is employed as the isoparan, butylenes and propylene areemployed as the heavier and lighter oleiinic reactants, respectively,and hydrogen tluoride catalysts are employed in both alkylationreactors, the catalysts having different concentrations of hydrogenfluoride therein. 'Ihe scope of the present invention is not limited tothe embodiments illustrated thereby. Further objects, embodiments, andillustrations indicative of the broad scope of the present inventionwill be apparent to those skilled in the art from the description of thedrawing and preferred embodiments of the invention hereinafter provided.

Referring to the drawing, isobutane is charged in conduit 1. The lighterolefnic reactant, comprising propylene, is charged through conduit 2 andpassed in conduit 1 in admxture with isobutane. The mixture of propyleneand isobutane is passed through conduit 1 and a portion thereof isdiverted through conduits 3 and 4 and the reactants in conduits 1, 3 and4 are passed separately into alkylation reactor 5 to insure thoroughmixing in reactor 5. In alkylation reactor 5 the isoparaflin and olefinare contacted and thoroughly admixed, with high strength hydrogenfluoride catalyst comprising about 95% acid to form a reaction mixture.Reactor 5 is provided with indirect heat exchange means not shown.Coolant is introduced through conduit 6 into reactor 5 and passed inindirect heat exchange with the reactants and catalyst therein. 'I'heheat exchange coolant is withdrawn from reactor 5 through conduit 7. Thereaction mixture is maintained at a temperature of about 90 F. and apressure sufficient to provide liquid phase operations in reactor 5.Reaction mixture, comprising catalyst, alkylated hydrocarbons, unreactedhydrocarbons such as isobutane, and possibly some propylene, iswithdrawn and passed via conduit 8 to a settler 9. In settler 9 highstrength hydrogen fluoride catalyst is separated from a hydrocarbonphase containing alkylated hydrocarbons, unreacted hydrocarbons andpossibly some alkyl fluoride compounds. The high strength hydrogenfluoride catalyst forms a separate heavier phase in settler 9 and iswithdrawn through conduit 10, passed through pump 13 and through conduit14, and thus recycled to reactor 5. A small portion of the high strengthcatalyst in conduit 10 is withdrawn through conduit 11 and passed to acatalyst regeneration operation not shown. Fresh and/or regeneratedcatalyst containing a high concentration of hydrogen fluoride, e.g., 97wt. percent is charged through conduit 12 to conduit 10 in order tomaintain the catalyst employed in reactor 5 at an optimum strength.Referring again to settler 9, the hydrocarbon phase comprisingalkylation reaction products, isobutane and possibly some alkylfluoride, etc., is rwithdrawn and passed through conduit 15. The heavierolenic reactant, co-mprising butylenes, is charged through conduit 16into conduit 15 and admixed with the hydrocarbon materials in conduit15. The admixed butylenes and hydrocarbon eluent from settler 9 arepassed further through conduit 5 into reactor 19. Portions of thecombined butylenes and hydrocarbon effluent in conduit 15 are divertedfrom conduit 15 to conduit 17 and conduit 18 and passed therethroughinto reactor 19 in order to provide thorough mixing with alkylationcatalyst in reactor 19. Reactor 19 is provided with indirect heatexchange means not shown. Coolant is charged to reactor 19 by way ofconduit 20. The coolant is passed in indirect heat exchange with thereaction mixture in reactor 19 and subsequently withdrawn throughconduit 21. The reactants charged to reactor 19 through conduits 15, 17and 18 are admixed with low strength hydrogen Huoride catalyst,containing about wt. percent acid, to form a reaction mixture in reactor19. The reaction mixture in reactor 19 is maintained at a temperature ofabout 90 F. in liquid phase operations. After the alkylation reaction issubstantially complete, reaction mixture is withdrawn from reactor 19and passed through conduit 22 into reaction soaker 23, lwherein thereaction mixture is maintained for an additional time at alkylationtemperature and pressure. The mixture is withdrawn from the reactionsoaker and passed through conduit 24 into settler 25. In settler 25, aheavier, low strength hydrogen uoride catalyst phase separates and iswithdrawn through conduit 26, passed through pump 29 and charged viaconduit 30 to reactor 19. A small portion of the low strength catalystin conduit 26 is withdrawn through conduit 27 and passed to regenerationnot shown. Fresh and/or regenerated catalyst is charged through conduit28 to conduit 26. Referring again to settler 25, a lighter, hydrocarbonphase, comprising alkylate product and unreacted isobutane, is withdrawnthrough conduit 31 and passed to conventional fractionation means, suchas an isobutane stripper, for further conventional separation of thealkylate product, and preferably, recycle of the isobutane to reactor 5.

PREFERRED EMBODIMENTS OF THE INVENTION The isoparaffinic and olenicreactants which are preferably employed in the process of the presentinvention are well known in the art. IIsobutane is the preferredisoparan, although isopentane, isohexane, and the like, may be employed.A suitable isoparatlinic reactant may contain some non-reactivecontaminants such as normal parains. For example, a typical commercialisobutane reactant may contain some propane and normal butane. Thepreferred heavier olenic reactant comprises butylenes. A preefrredoleinic reactant may comprise, for example, pure butene-l, purebutene-Z, pure isobutylene, or any mixture of two or all of the butyleneisomers. Also preferred for use as the heavier olefinic reactant is amixture of butylenes with some amylenes or other heavier olenicreactants. Other suitable heavier oleiinic reactants include C5 andheavier olens, but these may not provide results equivalent to thoseobtained with C4 olens. A preferred heavier olenic feed stock maycontain small amounts of such hydrocarbons as normal parafns,isoparafns, ethylene, propylene, etc.

The lighter olenic reactant is preferably propylene, and may suitably bepure propylene or may contain small amounts of parains, isoparains,ethylene, butylenes, etc. A typical commercial propylene alkylationreactant contains propylene and propane. It is preferred that theheavier olelinic reactants be substantially free .from the lighterolefin employed and, likewise, that the lighter olenic reactant besubstantially free from heavier olefin employed. By way 'of example, atypical preferred isoparatinic feed stock may contain, for example 95wt. percent isobutane, 1 wt. percent propane, and 4 wt. percent normalbutane, While a typical preferred heavier olenic reactant feed stock maycontain about 40 wt. percent butylenes, 45 Wt. percent isobutane and 15wt. percent normal butane, and a typical preferred lighter olefinicreactant feed stock may contain 60 wt. percent propylene and 40 wt.percent propane.

Alkylation catalysts which can be utilized inthe present invention,include alkylation catalysts known in the art. For example, strong acidssuch as hydrogen fluoride, sulfuric acid and phosphoric acid have Iallbeen employed. Other suitable catalysts include metal halides such asaluminum chloride, antimony halides, etc., boron halides, and certaincrystalline aluminosilicates catalytically active for alkylation ofisoparains, such as faujasite, mordenite, etc., either with or withoutthe addition of catalytic amounts of metals or metal ions.

In general, hydrogen uoride alkylation catalyst is preferred for use asan alkylation catalyst in the present process. Conventional hydrogenfluoride alkylation catalyst comprises about 75 wt. percent or more oftitratable acid and about 5 wt. percent or less Water, with theremainder made up of hydrocarbons and combined fluoride in solution inthe acid. Such a conventional alkylation catalyst is suitable for useboth as the alkylation catalyst in the first alkylation zone, foralkylating the isoparain with the lighter olenic reactant, and in thesecond alkylation zone for use with the heavier olenic reactant. In aparticularly preferred embodiment of the process of this invention, twodifferent strength hydrogen fluoride catalysts are employed. A higherstrength alkylation catalyst is preferably utilized in the lfirstalkylation zone to alkylate the isoparafn with the lighter olenicreactant, comprising preferably propylene. This higher strength catalystis characterized by a concentration of titratable acid of about 80 wt.percent to about 99 wt. percent a Water concentration of about 0.1 Wt.percent to about 1 wt. percent and a hydrocarbon concentration of about1 wt. percent to about wt. percent. A different, lower strength hydrogeniuoride alkylation catalysts is preferably utilized in the secondalkylation reaction zone in the reaction involving the heavier 'olenicreactant, preferably comprising butylenes. The lower strength alkylationcatalyst is characterized by a titratable acid concentration of about 65wt. percent to about 95 wt. percent, a water concentration of about 0.1wt. percent to about 1 wt. percent Iand a hydrocarbon concentration ofabout 5 wt. percent to about 35 wt. percent. A particularly preferredhigher strength catalyst contains about 90 wt. percent to about 9 wt.percent acid while a particularly preferred lower strength catalystcontains about 80 wt. percent to about 95 wt. percent acid.

Numerous alkylation reaction zones suitable for use in the process ofthis invention are known in the art. For example, but not by Way oflimitation, the alkylation reactors described in U.S. Pats. 3,456,033,3,469,949 and 3,501,536 may be suitably employed for both alkylationreactions when a fluid catalyst Such as the preferred hydrogen uoridecatalyst is utilized. Isoparain-oleiin alkylation conditions associatedwith the particular alkylation reactors described in the above-listedpatents or in connection with other suitable conventional alkylationreactors, are also well known and may be used in particular embodimentsof the present invention. The scope of the present invention is intendedto include, for example, embodiments of the present process in whichreactants and fluid catalysts are contacted in the alkylation zones andcatalyst is subsequently separated from the reaction products bysettling for further use. The scope of the present invention alsoincludes embodiments wherein beds of a solid catalyst, such as azeolitic catalyst, are employed in one or both of the reactors and thehydrocarbon effluent from the first reactor may thus be passed to thesecond reactor without further separation from the catalyst by settling.Particular alkylation zones and optimum alkylation conditions inspecific embodiments of the present process depend upon the compositionof the particular heavier oletnic reactant feed stream, the particularlighter olenic reactant feed stream, the isoparaflin feed stream, andthe type of catalyst employed. For example, in the preferred embodiment,isobutane and a lighter olenic reactant comprising about 50 volumepercent to about 70 volume percent propylene and about 30 volume percentto about 50 volume percent propane are contacted, at anisobutane/propylene mole ratio of about 5:1 to about 50:1, with ahydrogen uoride catalyst in a first alkylation reaction zone atalkylation conditions including a temperature in the range from about 0F. to about 200 F., a pressure suticient to maintain the hydrocarbonsand catalyst as liquids, a catalyst/hydrocarbon volume ratio in the rstalkylation reactor in the range from about 0.1:1 to about 10:1 and acontact time (defined as the volume of the alkylation reactor divided bythe volumetric iow rate, per minute of reactants and catalyst charged)in the first alkylation reactor in the range from about 0.1 minute toabout 30 minutes. In this preferred embodiment, a heavier olenicreactant comprising about 30 volume percent to about l60 volume percentbutylenes with the remainder made up of propane and butanes, iscontacted in a second alkylation reactor with the hydrocarbon effluentfrom the first alkylation zone, and with a hydrogen uoride catalyst, atalkylation conditions including a temperature in the range from about 0F. to about 200 F., a pressure suicient to maintain liquid phaseoperations, a catalyst/hydrocarbon volume ratio, in the secondalkylation reactor, of about 0.1:1 to about 10:1 and a contact time inthe second alkylation reactor in the range from about-0.1 minute toabout 30 minutes.

In a particularly preferred embodiment, alkylation conditions in the rstalkylation zone include employment of the preferred high strengthhydrogen fluoride alkylation catalyst described above and also include atemperature of about 60 F. to about 150 F., with a temperature of about75 F. to about 120 F. particularly preferred, a pressure sufficient tomaintain the reactants and catalyst as liquids, and a reaction time ofabout 0.1 minute to about 20 minutes. Preferably, in this particularembodiment, isobutane and propylene reactants are charged to the Vfirstalkylation reactor at a mole ratio of about 20:1 to about 30:1, and acatalyst-to-hydrocarbon volume ratio of about 0.5 :1 to about 2:1 ismaintained in the rst alkylation zone. Likewise, in this particularpreferred embodiment, alkylation conditions in the second alkylationreactor include the use of the preferred low strength hydrogen fluoridealkylation catalyst, as described above, and also include a temperatureof about 40 F. to about F., with a temperature of about 50 F. to about100 F. particularly preferred, a pressure sufficient to maintain thereactants and catalyst as liquids, and a reaction time of about 0.1minute to about 20 minutes. Preferably, the hydrocarbon eluent from thefirst alkylation zone and the heavier olenic reactant, comprisingbutylenes, are charged to the second alkylation reactor at abutylenes-to-hydrocarbon eiiluent mole ratio of about 1:20 to about1:30, and a catalyst-to-hydrocarbon volume ratio of about 0.5 :1 toabout 2:1 is maintained in the second alkylation reactor. By maintainingthe above-described preferred conditions in the rst alkylation zone andsecond alkylation zone respectively, when using propylene as the lighterolefinic reactant and butylenes as the heavier olenic reactant, it ispossible to provide an optimum yield of high quality alkylate productfrom both the propylene alkylation reaction and the butylenes alkylationreaction. The desirable high molar ratio of isobutane is also maintainedin both the first and second alkylation reaction zones Without thenecessity of maintaining enough surplus isobutane to provide separatecharges of excess isobutane to the separate reactors as taught in priorart. By employing the hydrocarbons, particularly isobutane, requiredinthe second alkylation zone, the same charge of hydrocarbons acts, inpart, as the excess required in both the lighter olefin alkylationreaction and the heavier olefin alkylation reaction. By utilizingpropylene as the lighter olenic reactant, and maintaining theabove-described preferred alkylation conditions in the rst alkylationzone, self-alkylation of isobutane, the preferred isoparafn reactant, isenhanced. Under the preferred conditions employed in the firstalkylation zone, propylene reacts with isobutane to provide propane andisobutylene, in what is known in the art as the hydrogen transferreaction. The isobutylene thus formed reacts in an alkylation reactionwith further isobutane to provide primarily high octane C8 hydrocarbons.Thus, while more isobutane may be consumed in the preferred embodimentof the present process than in some conventional alkylation processes,the increased consumption would be more than offset by the products ofadditional amounts of superior alkylate product.

In the preferred embodiment, the reaction mixture formed in the secondalkylation reactor is passed through a reaction soaker. In thedescription of the preferred embodiments herein provided, it is intendedthat both the second alkylation reactor and the reaction soaker, as wellas a settler, are included within the scope of the term secondalkylation zone. Suitable reaction soakers are well known in the art.For example, the reaction soakers described in U.S. Pats. 3,560,587 and3,607,970 may suitably be employed in the present process. Such reactionsoakers are commonly vessels equipped with perforated trays, baillesections, or the like, to maintain the mixture of catalyst andhydrocarbons charged from the second alkylation reactor as a fairlyhomogenous mixture at alkylation temperature and pressure for apredetermined length of time. The mixture of catalyst and hydrocarbonsis maintained in the reaction soaker for a time which depends on thecomposition of the reaction mixture. A reaction soaker residence time ofabout 1 minute to about 30 minutes is preferred. The temperature andpressure maintained in the reaction soaker are the same as thetemperature and pressure maintained in the second alkylation reactor.

Means for separating a hydrocarbon phase from, for example, a fluidcatalyst phase, such as a hydrogen fluoride catalyst, in the eluent froman alkylation reactor' or reaction soaker are well known in thealkylation art. Generally, when a Huid catalyst such as hydrogenfluoride is employed in the present process, the effluent from analkylation reactor or soaker comprises a mixture of isoparan, reactionproducts, catalyst and catalyst-soluble organic materials with smallamounts of olefin-acting compounds, light hydrocarbon gases, etc. Whenthis mixture is allowed to stand unstirred, i.e., settled, the reactionproducts, isoparaiin, light hydrocarbon gases, and possibly some organicfluorides, from a hydrocarbon phase, possibly containing a small amountof catalyst in solution. The catalyst and catalyst-soluble hydrocarbonsform a separate phase. The hydrocarbon phase is thus easily mechanicallyseparated from the catalyst phase. The temperature and pressuremaintained dun'ng such a settling operation in an alkylation process,required when a fluid catalyst is utilized, are substantially the sameas those described in connection with alkylation reaction conditionsemployed in the reactor. The hydrocarbons and the catalyst arepreferably maintained in the liquid phase during the separationoperation. The term alkylation zone is intended to include a settler aswell as a re- 8 actor, Where a settler is required in order to separatethe hydrocarbons from the catalyst, c g., when hydrogen fluoridecatalyst is employed.

Some means for withdrawing heat from the alkylation zones is usuallynecessary for satisfactory operation of the process. A variety of meansfor accomplishing the heat withdrawal are Awell known. For example, in apreferred embodiment the heat generated by the alkylation reaction maybe withdrawn directly from the alkylation reactor by indirect heatexchange between cooling water and the reaction mixture in the reactor.

The hydrocarbons stream, or phase, recovered, in the preferredembodiment, from the first alkylation reactor by settling the reactionmixture eluent therefrom, is combined with the heavier olenic reactant,preferably butylenes, and charged to the second alkylation reactor,wherein this combined hydrocarbons stream is contacted with analkylation catalyst. It is contemplated that sucient isoparafiin ischarged to the first reactor so that no further isoparatin need be addedto the hydrocarbons charged to the second reactor. Generally, the totalisobutane charged to the alkylation process is passed through, in turn,the first alkylation zone and the second alkylation zone. Under someconditions, it may be advantageous to charge some further isobutane tothe second alkylation reactor, and such a modification is within thescope of this invention. The second hydrocarbons stream, recovered fromthe second alkylation zone, is passed to further conventional separationoperations and equipment, such as a fractionator, whereby the alkylationproduct is separated from unconsumed isoparain and any entrained ordissolved catalyst such as hydrogen fluoride, if any, which is presentin the hydrocarbons eflluent from the second alkylation zone. Anysuitable method utilized in the prior art to separate the alkylateproduct from the isoparain and, for example, hydrogen fluoride, may beemployed in the present process.

The alkylation reaction product produced in the improved process of thisinvention includes primarily C7 and C8 saturated hydrocarbons resultingfrom the alkylation reactions of the isoparaflin with both the lighterand t he heavier olenic reactants. The primary products include, forexample, dimethylpentanes and trimethylpentane. It is well known thatmore highly branched hydrocarbons possess superior properties as motorfuel, and the present invention is directed, in part, to providingalkylate from the process containing a higher ratio of more highlybranched hydrocarbons, such as trimethylpentanes, to less branchedhydrocarbons, such as dimethylhexanes. Thus, it is apparent that thepresent invention provides a novel process for producing a superior a1-kylate product by a method more economical and convenient than has beenavailable in the prior art.

EXAMPLE I A supply of mixed butylenes charge stock was obtained andanalyzed. It was found to contain 50 wt. percent butene-2, 28 wt.percent isobutylene and 22 wt. percent butene-l. A supply of propylenecharge stock was obtained and analyzed and found to contain 99.6 wt.percent propylene. A supply of isobutane charge stock was obtained, andanalysis showed that it contained 96 wt. percent isobutane, 3 wt.percent normally butane and 1 wt. percent propane.

Organic catalyst diluent was prepared, as needed for use in alkylationcatalysts by charging 4 liters of isobutylene and 1.6 liters of 99 wt.percent hydrogen iluoride to an 8.81 liter stirred autoclave under a 200p.s.i. nitrogen atmosphere, allowing the olen and catalyst to react forone hour at 60 C., and then separating the diluent from the acid.Analysis of the diluent showed that it comprised polyisobutylenes havinga molecular weight in the range from about 200 to about 500'.

In order to demonstrate the utility of the process of the presentinvention, a portion of the propylene charge stock was mixed with aportion of the isobutane charge stock at an isobutane/propylene moleratio of 24:1. This mixture was continuously charged to an 'alkylationreactor at the rate of 0.5 mole propylene per hour and 12 molesisobutane per hour. Simultaneously, hydrogen uoride alkylation catalystcontaining 95 lwt. percent hydrogen fluoride, 4 wt. percent organicdiluent and l wt. percent water was also continuously charged to thereactor. The alkylation reactor Was equipped with stirring means andmeans for removing excess heat of reaction. An acid/hydrocarbon volumeratio of 3/ 2 was maintained in the reactor. The reaction mixture formedin the alkylation reactor was maintained at a temperature of 105 F. anda pressure of 15 atmospheres. A residence time (dened as the volume ofthe reactor divided by the total volume of reactants and catalystcharged per minute) of 10 minutes was maintained. The reaction mixturewas continuously withdrawn from the alkylation reactor, passed into asettling vessel, and held at a residence time of minutes, whereby themixture was separated into a catalyst phase and a hydrocarbon phase. Thecatalyst phase was recovered and recycled to the alkylation reactor forfurther use. The hydrocarbon phase was withdrawn from the settler andrecovered. 'Ihe hydrocarbons thus recovered from the settler werecontinuously charged to an alkylation reactor identical to the one used,as described above, to react the propylene. A portion of theabove-described butylenes feed stock vvas admixed with the hydrocarbonphase and continuously charged to the alkylation reactor at the rate of0.5 mole of C4 oleiins per hour. Simultaneously, hydrogen iluoridealkylation catalyst containing 75 wt. percent hydrogen fluoride, 24 wt.percent organic diluent and 1 wt. percent water was also charged to thealkylation reactor. An acid/hydrocarbon volume ratio of 3/2 wasmaintained in the reactor. The reaction mixture formed from the catalystand hydrocarbons was held at a temperature of 90 F. and a pressure of 15atmospheres for a residence time of minutes. The reaction mixture wascontinuously withdrawn from the alkylation reactor, charged to asettling vessel and settled to provide a catalyst phase and ahydrocarbon phase. The catalyst phase was continuously removed andrecycled to the alkylation reactor for further use. The hydrcarbon phasewas continuously withdrawn from the settling vessel. The C5 and heavierhydrocarbons in this hydrocarbon phase were separated and recovered asthe product of the alkylation process. When this product was analyzed,it was found to have a clear research octane number of 95.2 and a clearmotor octane number of 92.5.

EXAMPLE 1I In order to demonstrate the superiority of the process of thepresent invention over other methods for alkylating isobutane withpropylene and butylenes, a portion of the same butylenes charge stockused in Example I was mixed with a portion of the same isobutane chargestock used in Example I at an isobutane/C4 oleiins mole ratio of 24:1:This mixture was continuously charged to an alkylation reactor identicalto those used in Example I at the rate of 0.5 mole of C., olens per hourand 12 moles isobutane per hour. Simultaneously, hydrogen fluoridealkylation catalyst containing 5 wt. percent hydrogen fluoride, 24 wt.percent organic diluent and l wt. percent water was also continuouslycharged to the reactor. An acid/hydrocarbon volume ratio of 3/2 wasmaintained in the reactor. The reaction mixture formed in the alkylationreactor was maintained at a temperature of 90 F. and a pressure ofatmospheres for a residence time of 10 minutes. The reaction mixture wascontinuously Withdrawn from the alkylation reactor, passed into asettling vessel and held therein for a residence time of 5 minutes,whereby a catalyst phase and a hydrocarbon phase were separated. Thecatalyst phase was withdrawn from the settler and recycled to thealkylation reactor for further use. The hydrocarbon phase was withdrawnfrom the settler and recovered. The hydrocarbons thus recovered from thesettler were continuously charged to an alkyltion reactor identical tothe one used as described above. A portion of the same propylene chargestock used in Example I Was admixed 'with the hydrocarbons from thesettler and continuously charged with them to the reactor at a rate of0.5 mole propylene per hour. Simultaneously, hydrogen uoride alkylationcatalyst containing wt. percent hydrogen fluoride, 4 wt. percent organicdiluent and l'wt. percent water, was also continuously charged to thereactor. An 'acid/hydrocarbon volume ratio of 3/2 was maintained in thereactor. The reaction mixture formed in the alkylation reactor was heldat a temperature of F. and a pressure of 15 atmospheres for a residencetime of 10 minutes. The reaction mixture was continuously withdrawn fromthe alkylation reaction mixture was continuously withdrawn from thealkylation reactor, passed into a settling vessel and held for aresidence time of 5 minutes, whereby the Areaction mixture settled intoa catalyst phase and a hydrocarbon phase. The catalyst phase wascontinuously Withdrawn from the settling vessel and recycled to thereactor for further use. The hydrocarbon phase was continuouslyWithdrawn from the settling vessel. The C5 and heavier hydrocarbons inthis hydrocarbon phase were separated and recovered as the product ofthe process. When this product was analyzed, it was found to have aclear research octane number of 94.5 and a clear motor octane number of92.0.

By a comparison of the octane numbers of the 'alkylate product obtainedas described in Example I with the octane numbers of the productobtained as described in Example II, it is evident that the method ofthe present invention, as embodied in Example I, is substantially andquite surprisingly superior to the method described in Example II.Although the reasons for the unexpected superiority of the alkylateproduct in Example I over that in Example II are not completely known,the superiority may be due, in part, to the degradation in the secondreactor of the alkylate formed in the first reactor in Example II whenit is subjected to the relatively severe conditions, ideal foralkylation of propylene, in the second reactor. Comparison of Example Iwith Example II further shows that merely by utilizing the rst reactorto alkylate propylene and the second reactor to alkylate butylenes,rather than Vice versa, even when identical reactors and reactionconditions are used, as in Example II, a substantially superior productmay be recovered by the method of the present invention, while there isno increase in consumption of reactants, utilities, etc.

EXAMPLE I-II In order to illustrate the flexibility of optimumalkylation conditions which may be employed for the alkylation ofbutylenes in the process of the present invention, a portion of thepropylene charge stock described in Example I was combined with aportion of the isobutane charge stock also described in Example I at anisobutane/ propylene mole ratio of 24:1. The combined isobutane andpropylene were charged to an alkylation reactor identical to the reactoremployed in Example I for the propylene-isobutane reaction. Theisobutane and propylene were charged continuously to the reactor at anisobutane flow rate of 12 moles per hour and a propylene ow rate of 0.5mole per hour. Hydrogen fluoride alkylation catalyst, containing 95 wt.percent hydrogen iluoride, 4 wt. percent organic diluent and 1 wt.percent Water was also continuously charged to the reactor. The catalystand hydrocarbons were contacted to form a reaction mixture and thereaction mixture was maintained at an acid/ hydrocarbon volume ratio of3/ 2, a temperature of 90 F. and a pressure of 15 atmospheres for aresidence time of 10 minutes. Reaction mixture was continuouslyWithdrawn from the reactor and passed to a settling vessel,

wherein it was held for a residence time of minutes, forming a catalystphase and a hydrocarbon phase. The catalyst phase was continuouslywithdrawn from the settling vessel and recycled to the reactor forfurther use. The hydrocarbon phase was withdrawn from the settler andrecovered. The hydrocarbons thereby recovered from the settler werecontinuously charged to an alkylation reactor identical to the one used,as described above, to react the propylene and isobutane. A portion ofthe butylenes feed stock described in Example I was admixed with thehydrocarbons and also continuously passed to the reactor. The butyleneswere charged to the reactor at a flow rate of 0.5 mole per hour.Hydrogen fluoride alkylation catalyst, containing 89 wt. percenthydrogen uoride, 9 wt. percent organic diluent and 1 wt. percent Water,was simultaneously charged to the alkylation reactor. The hydrocarbonsand catalyst were admixed to form a reaction mixture having anacid/hydrocarbon volume ratio of 3/2, and the reaction mixture was heldat a temperature of 90 F. and a pressure of yl5 atmospheres for aresidence time of 10 minutes. Reaction mixture was continuouslywithdrawn from the reactor, passed to a settling vessel, and heldtherein for a residence time of 5 minutes, forming a catalyst phase anda hydrocarbon phase. The catalyst phase was continuously Awithdrawn fromthe settler and recycled to the reactor for further use. The hydrocarbonphase was withdrawan from the reactor. The C5 and heavier hydrocarbonsin the hydrocarbon phase were separated and recovered as the alkylateproduct. 'Ihis alkylate product Was analyzed and found to have a clearresearch octane of 96.2.

By contrasting the conditions employed and the quality of the alkylateproduced in Example il with the conditions used and the quality of thealkylate of Example III, it can be seen that by Varying the temperaturesin the first reactor and second reactor, and by using a higher strengthacid in the second reactor in Example III, a product of significantlyhigher quality was produced. This surprising result is particularlyunexpected, since the quality of the alkylate produced in Example I issubstantially higher than that of alkylate produced from the samereactants by conventional methods, and the quality of the alkylate ofExample I was also substantially higher than alkylate produced byreversing the order of reaction of the propylene and butylenes, asdescribed in Example II.

Examples I and III clearly demonstrate the wide range of conditions atwhich the present process, particularly the second, butylenes alkylationoperation, may be performed. By adjusting the conditions in the second,butylenes stages of the proces to provide optimum butylenes alkylationconditions, while maintaining the second stage conditions as mild aspossible to prevent degradtion of the alkylate produced in the first,propylene alkylation stage, a particularly eicient and satisfactoryprocess is achieved. This is particularly true in contrast to performingan alkylation process by the method of Example II, where propylene isreacted in the second stage. Propylene alkylation conditions, ingeneral, are not as ilexible as butylenes alkylation conditions.Further, the propylene alkylation conditions must, in general, be moresevere than butylene alkylation conditions to provide a satisfactoryproduct.

EXAMPLE IV The superior ilexibility of the process of the presentinvention in contrast to the method of Example II was furtherdemonstrated by varying the alkylation conditions using the process ofExample II. A portion of the same butylenes charge stock employed inExample I was mixed with a portion of the same isobutane charge stock asused in Example I. The mixture was made at a 24:1 isobutane/ butylenesmole ratio. The isobutanebutylenes mixture was continuously charged toan alkylation reactor identical to those employed in Example I at a flowrate of 0.5 mole butylenes and 12 moles isobutane per hour. Hydrogenuoride alkylation catalyst containing 75 Wt. percent acid, 24 wt.percent organic diluent, and 1 Wt. percent water was also continuouslycharged to the reactor. The catalyst and hydrocarbons were admixed at acatalyst/ hydrocarbon volume ratio of 3/2. The reaction mixture wasmaintained at a temperature of F. and a pressure of l5 atmospheres for aresidence time of 10 minutes. Reaction mixture was continuouslywithdrawn and passed to a settling vessel and held therein for a5-minute residence time. A catalyst phase and a hydrocarbon phase wasthereby settled out. The catalyst phase was withdrawn from the settlerand recycled to the reactor for further use in the butylenes alkylationreaction. The hydrocarbon phase was recovered from the settler andcontinuously passed to an alkylation reactor identical to the one usedin the first stage. A portion of the same propylene charge stock used inExample I was admixed with the hydrocarbons recovered from the settlerand was thereby also passed to the second stage reactor at a rate of 0.5mole per hour. Hydrogen iiuoride catalyst containing Wt. percent acid, 4wt. percent organic diluent, and 1 Wt percent water was simultaneously,continuously charged to the second stage reactor. A catalyst/hydrocarbonvolume ratio of 3/2 was maintained. The mixture of hydrocarbons andcatalyst was maintained at a temperature of 90 F. and a pressure of l5atmospheres for a residence time of 10 minutes. Reaction mixture wascontinuously Withdrawn from the second stage reactor, passed to asettler and held therein for a 5-minute residence time. A catalyst phaseand a hydrocarbon phase were separated, and the catalyst phase wascontinuously withdrawn from the settler and recycled to the second stagereactor for further use. The hydrocarbon phase was withdrawn from thesettler and fractionated. The C5 and heavier hydrocarbons were separatedfrom the lighter hydrocarbons and recovered as the alkylate product ofthe process. When the alkylate product was analyzed, it was found tohave a clear research octane number of 95.

Contrasting Examples I and III, wherein propylene is alkylated in thefirst stage and butylenes are alkylated in the second stage, accordingto the process of the present invention, with Examples II and IV,wherein butylenes are alkylated in the first stage and propylene in thesecond, it is apparent that the process of the present invention hasgreater flexibility and provides a clearly superior alkylate product. Inboth Examples III and IV, propylene was alkylated utilizing the sametemperature and acid strength, and the second stage in both theseexamples was operated at a temperature of 90 F. Yet the method ofExample III, employing the present inventive process, produced a clearlysuperior alkylate product. By adjusting reaction conditions, Example IVproduced only a one-half research octane number increase in the alkylateproduct over Example II. In contrast, by adjustment of the alkylationreaction conditions in Example III, an octane -number increase of onenumber was achieved over the alkylate of Example I. Further, even byadjusting reaction conditions in Example IV, the method of the presentinvention used in Example I to provide an alkylate product having anoctane number at the lower end of the range obtained using the presentprocess, provided an alkylate product superior to that obtained by themethod of Examples II and IV.

EXAMPLE V In order to illustrate some of the advantages of the processof the present invention over conventional methods for producingalkylate, a conventional operation is performed. Portions of thepropylene charge stock and isobutane charge stock described in Example Iare combined at an isobutane/propylene mole ratio of l2 to 1. Thereactants are contuously charged to an alkylation reactor identical tothe one used to alkylate propylene in Example I. The flow rate ofreactants is maintained at 6 moles per hour of isobutane and 0.5 moleper hour of propylene. Hydrogen uoride alkylation catalyst, containing95 Wt. percent hydrogen fluoride, 4 wt. percent organic diluent and 1wt. percent water, is also continuously charged to the reactor. Thehydrocarbons and catalyst are admixed at an acid/hydrocarbon volumeratio of 3/2 and the reaction mixture is maintained at a temperature of90 F. and a pressure of 15 atmospheres for a residence time of 10minutes. The reaction mixture is continuously withdrawn from the reactorand passed to a settling vessel. 'Ihe reaction mixture is held in thesettler for a residence time of 5 minutes, whereby a catalyst phase anda hydrocarbon phase are formed. The catalyst phase is withdrawn from thesettler and recycled to the reactor for further use. The hydrocarbonphase is withdrawn from the settler and recovered. Portions of thebutylenes charge stock and isobutane charge stock described in Example Iare combined at an isobutane/ butylenes mole ratio of 12 to 1. Thesereactants are continuously charged to an alkylation reactor, identicalto the one used to alkylate butylenes in Example I, at an isobutane flowrate of 6 moles per hour and a butylenes flow rate of 0.5 mole per hour.Hydrogen uoride alkylation catalyst, containing 90 wt. percent hydrogenuoride, 9 wt. percent organic diluent and 1 wt. percent water is alsocharged continuously to the reactor and combined with the hydrocarboncharge at an acid/hydrocarbon volume ratio of 3/2. The resultingreaction mixture is held at a temperature of 90 F. and a pressure of 15atmospheres for a residence time of 10 minutes. Reaction mixture iscontinuously withdrawn from the reactor, passed to a settler, andseparated therein into a catalyst phase and a hydrocarbon phase. Aresidence time in the settler of 5 minutes is maintained. The catalystphase is continuously withdrawn from the settler and recycled to thereactor for further use. The hydrocarbon phase is withdrawn from thesettler and combined with the hydrocarbon phase recovered from thepropylene alkylation settler described above. The C5 and heavierhydrocarbons from this combined hydrocarbon phase are separated from thelighter hydrocarbons and recovered as the product of the process. Thisalkylate product is analyzed and found to have a clear research octanenumber of 94.5.

By comparing the quality of the alkylate produced in Example V with thequality of the alkylates produced in Example I and Example III, it canbe seen that the process of the present invention is capable ofproducing a substantially superior alkylate product. Comparing theamount of reactants charged in Examples I and III with the amount ofreactants charged in Example V shows that the exact same amounts ofreactants were used in all three examples, with substantially the samealkylation conditions used in the reactors. Thus, the superiority of theprocess of this invention is clearly demonstrated.

EXAMPLE VI The process of the present invention is further compared withconventional alkylation techniques by performing a typical conventionalalkylation process wherein the propylene and butylene reactants arecombined. The same propylene, butylene, and isobutane reactants asemployed in Example I are utilized. The reactants are admixed to providea 24:1 isobutane/propylene mole ratio, a 24:1 isobutane/butylenes moleratio and an overall isobutane/olens mole ratio of 12:1. 'Ihe reactantsare continuously charged to an alkylation reactor identical to thoseemployed in Example I. A flow rate of 12 moles per hour of isobutane,0.5 mole per hour of butylenes and 0.5 mole per hour of propylene ismaintained. Simultaneously, hydrogen fluoride catalyst containing 89 wt.percent acid, 10 wt. percent organic diluent and 1 wt. percent Water isalso charged to the reactor. A 3/2 volume ratio of catalyst tohydrocarbons is maintained in the reaction mixture. A temperature of 90F. and a pressure of 15 atmospheres are also maintained. After aresidence time of 10 minutes, the reaction mixture is continuouslywithdrawn from the reactor, passed to a settler, and held therein for 5minutes residence time. The resulting catalyst phase is withdrawn fromthe settler and recycled to the reactor for further use. The hydrocarbonphase resulting from the settling operation is withdrawn from thesettler and fractionated. 'Ihe C5 and heavier hydrocarbons in thehydrocarbon phase are separated and recovered as the alkylate product ofthe process. This alkylate product is analyzed and found to have a clearresearch octane number of 93.5.

Comparing the alkylate product produced, according to the process of thepresent invention, by the methods in Examples I and III, with thealkylate product produced by the conventional alkylation technique ofExample VI, it is apparent that the present process provides asurprising and substantial improvement in the quality of the alkylaterecovered, while using the same amounts of reactants. Using identicalamounts of the oleiinic reactants and isobutane, the method of ExampleIII produced an alkylate having a research octane number of 96.2, whilethe conventional, commercial method of Example VI produced an alkylatehaving a research octane number of only 93.5.

EXAMPLE VII A proce/ss according to the present invention, identical tothat used in Example III, was employed, the only difference being that atemperature of 68 F. was maintained in the second stage reactor whereinthe butylenes reactant Was alkylated, in contrast to Example III, inwhich a temperature of F. was employed. The hydrocarbons removed fromthe second stage settler were separated into a C5| fraction and a C4 andlighter fraction. The C54- fraction was recovered as the alkylateproduct of the operation and analyzed. It was found to have a researchoctane number of 96.2, identical to that of the alkylate produced by themethod of Example III. Thus, the flexibility of the conditions which maybe employed to alkylate butylenes according to the process of thepresent invention was further demonstrated.

EXAMPLE VIII In a further demonstration of the utility of the process ofthe present invention, the alkylate products produced in Examples II,III, and VII were further analyzed to determine the friction of C9 andheavier hydrocarbons produced by the embodiments of these examples. Itwas found that the alkylate product produced in Examples III and VII, bythe process of the present invention, contained only 4 wt. percent C9and heavier hydrocarbons, while the product produced using the method ofExample II, by merely reversing the order of reaction of the lighter andheavier olens from the order taught according to the process of thisinvention, contained 6.2 wt. percent C9 and heavier hydrocarbons. Thealkylate product obtained by the conventional processes of Examples Vand VI is also analyzed and found to comprise 5 wt. percent C9 andheavier hydrocarbons. It is thus apparent that the process of theinvention provides a method for producing an alkylate product having anend boiling point substantially below the end points of alkylatesobtained using prior art and other alkylation processes.

I claim as my invention:

1. A process for producing an alkylation reaction product from anisoparan reactant, a lighter oleiinic reactant and a heavier olenicreactant which comprises the steps of:

(a) contacting said isoparainic reactant and said lighter oleinicreactant -with a rst alkylation catalyst in a first alkylation zone atrst alkylation conditions;

(b) settling from .said rst alkylation zone a first hydrocarbon phasewhich comprises a portion of said isoparainic reactant and a portion ofsaid alkylation reaction product;

(c) contacting said heavier olelinic reactant and at least a portion ofsaid irst hydrocarbon phase with a second alkylation catalyst in asecond alkylation zone at second alkylation conditions;

(d) settling from said second alkylation zone a second hydrocarbon phasewhich comprises at least a portion of said alkylation reaction product;and

(e) recovering said alkylation reaction product from said secondhydrocarbon phase.

2. The process of claim 1 wherein said lighter olefinic reactantcomprises propylene.

3. The process of claim 1 wherein said heavier oleiinic reactantcomprises butylenes.

4. The process of claim 1 wherein said rst alkylation catalyst ishydrogen uoride alkylation catalyst.

5. The process of claim 1 wherein said second alkylation catalyst ishydrogen uoride alkylation catalyst.

6. The process of claim 4 wherein said first alkylation catalyst is ahydrogen fluoride alkylation catalyst comprising about 80 wt. percent toabout 99 wt. percent hydrogen fluoride and said first alkylationconditions include a temperature of about 60 F. to about 150 F.

7. The process of claim 5 wherein said second alkylation catalyst is ahydrogen iiuoride alkylation catalyst comprising about 65 Wt. percent toabout 95 Wt. percent hydrogen uoride and said second alkylationconditions include a temperature of about 0 F. to about 110 F.

8. The process of claim 1 wherein an isoparaflinic recycle stream isrecovered from said second hydrocarbon phase and at least a portion ofsaid isoparanic recycle stream is introduced into said rst alkylationzone.

9. The process of claim 1 wherein said isoparanic reactant comprisesisobutane.

10. The process of claim 1 wherein said first alkylation catalyst isselected from sulfuric acid, phosphoric acid and a crystallinealuminosilicate catalytioally active for isoparafn-olefin alkylation.

11. The process of claim 1 wherein said second alkylation catalyst isselected from sulfuric acid, phosphoric acid and a crystallinealuminosilicate catalytioally active for isoparaflinolen alkylation.

12. The process of claim 6 wherein said rst alkylation conditionsinclude a temperature of about F. to about 120 F. and said rstalkylation catalyst comprises about wt. percent to about 99 wt. percenthydrogen fluoride.

13. The process of claim 7 wherein said second alkylation conditionsinclude a temperature of about 50 F. to about F. and said secondalkylation catalyst comprises about 70 wt. percent to about 95 wt.percent hydrogen uoride.

References Cited UNITED STATES PATENTS 2,312,539 3/1943 Frey 260-683.452,415,717 2/ 1947 Watkins et al. 260-683.45 2,427,293 9/ 1947 Matuszak260-683.61 3,211,803 10/1965 Chapman 260-683.49 3,236,912 2/ 1966Phillips 260-683.49

DELBERT E. GANTZ, Primary Examiner G. d. CRASANAKIS, Assistant ExaminerU.S. C1. X.R.

